How to deal with slag hanging in laser cutting?

The residue left after cutting the metal surface is called dross.

The residue left after cutting the metal surface is called dross. When the laser cutting machine cuts metal materials, a lot of heat is generated. After focusing through special parts, a small light spot is formed at a specific position.

Moreover, the focus can reach high temperature and power at a specific position, and only a small part of the heat formed locally will be transferred to other parts, and the part of the heat consumed by conduction is much smaller than the heat input by the laser beam. Therefore, the material can be heated to the degree of vaporization very quickly at the focal position, and holes and gaps can be formed through vaporization and evaporation. The entire piece of material is then sufficiently cooled. However, when cutting parts with small holes, the outer side of the hole can be fully cooled, but the inner side of the hole has limited space for heat diffusion, and the heat cannot be dissipated in time, so the phenomenon of slag hanging occurs. In addition, when cutting thick plates, the accumulation of heat due to the thickness of the plate will cause disturbance of the auxiliary airflow, excessive heat input, and slag hanging.

In fact, the burr that is usually mentioned is the hanging slag, that is, the cutting residue on the surface of the metal material. When the laser cutting machine is cutting metal materials, a large amount of heat is generated when the laser beam irradiates the surface of the metal material, which vaporizes the surface of the material, and then evaporates to achieve the purpose of cutting. But we have to pay attention to an important point, and that is the gas.

The main function of the gas is to blow off the slag on the surface of the cutting part when the laser beam vaporizes the surface of the material. If the gas is not used during the cutting process, the slag will form a burr after cooling.

Another factor may be the quality of the cutting equipment, as well as the parameter setting of the cutting equipment. After the customer purchases the laser cutting equipment, the manufacturer will arrange an experienced operator to go to the customer site to debug the laser cutting equipment. Parameters including air pressure, flow rate, focal length, cutting, speed and other parameters of the equipment have been adjusted many times to achieve excellent work efficiency.

If there is slag hanging on the cutting parts, first find the cause from the following points. After finding the problem, reasonable debugging can solve the slag hanging phenomenon.

1. The laser output power is not enough

2. The focus of the laser beam is deviated

3. The air pressure of the auxiliary gas is not enough

4. Cutting speed is too fast or too slow

By solving the above four elements of the equipment, the problem of hanging slag can be well dealt with, so that almost perfect cutting parts can be cut.